Separation of pyrochlore from calcite, apatite and silica



Sept 6, 1950 H. G. uRKs 2,951,585

SEPARATION OFNPYROCHLORE FROM CALCITE, APATITE AND SILICA Filed Sept. 8, 1958 Reagent FeederI edge/: fem? lah ConZm//ef Cond/ifo 6F Unite States Patent O SEPARATION OF PYROCHLORE FROM CALCITE, APATITE AND SILCA Herbert George Barks, P1). Box 69, Dodoma, Tanganyika, East Africa Filed Sept. 8, 1958, Ser. No. 759,768

7 Claims. (Cl. 209-167) This application relates to the separation of pyrochlore from calcite, apatite and silica, and is a continuationin-part of application Serial No. 615,777, filed October 15, 1956, now abandoned.

According to the invention, pyrochlore is separated from mineral containing calcite, apatite and silica. by a process which comprises subjecting the ore to froth otation in the presence of at least one aliphatic monoamine or diamine thereof containing from 14 to 20 carbon atoms in the molecule, to float the pyrochlore and silica away from` the calcite and epatite, treating the float product with a depressant in a quantity su'icient to neutralize the actuating effect of the amine, and thereafter subjecting the product to froth liotation in the presence of an unreacted aliphatic monoamine or acetate lthereof containing from 10 to 12 carbon atoms in the molecule to float the pyrochlore away from the silica.

There are commercially available a number of amines having 14 to 20 carbon atoms in the molecule, the selection of any one of which would be acceptable for the purposes of the present invention. As examples of such amines, there are given the following under the designation of their trade names: Amine 1180, Duomeen T, Amine 220, and Rosin Amine D Acetate. The preliminary or first flotation step is for the purpose of floating the pyrochlore and all other minerals except calcite and apatite which are discarded as tailing. Use of the larger carbon chain amine makes possible such greater selection without attendant critical conditions of operation, as would be necessary if an amine yof smaller carbon chain were employed.

Preferably the rst flotation step is carried out in the presence of a wetting agent, advantageously an alkyl aryl sulphonate. As examples of such wetting agents are given those known under the trade names Ultrawet 40A, Calsolene Oil HS, and Lissapol N.

The float product from the first flotation step is cleaned by floating without further reagent -addition and the tailing from this cleaning operation may be tabled to recover any coarse pyrochlore which fails to oat.

The concentrate is then treated with a depressant in a quantity sufficient to neutralize the actuating effect of the amine. Preferably, a solution of sodium silicate is employed for this purpose. Examples of other depressants are quebracho extract and other tannin containing materials. It wll be apparent that the amount of depressant added will vary with the particular ore under treatment. The amount of such depressant may readily be determined for each particular ore by practical methods well known to a skilled operator in the art of flotation. As indicated above, only sufficient depressant is employed to effect the desired neutralization so that on completion of this step of the treatment, no depressant remains in the concentrate.

lf any considerable amount of iron is present as sulphide, this, as well as any ne mica present, can be oated away from the pyrochlore and silica in an intermediate froth dotation step carried out in the presence of a frother, such as methyl isobutyl carbinol or any other alcohol-type frother. The tailings, containing the pyrochlore, may pass to a wet magnetic separator for the removal of magnetite and some ilmenite.

The pyrochlore containing material is now subjected to a selective flotation treatment using an aliphatic monoamine containing from 10 to l2 carbon atoms to the molecule, preferably dodecylamine, the pH being adjusted to 5.5-6 with, for instance, sulphuric acid. This treatment oats away the pyrochlore from silica, coarse mica, and silicates.

If iron is present, it is advantageous to carry out the second flotation step in the presence of an agent which forms a complex ion with iron, such as citric acid, tartaric acid, sodium uoride, sodium hexametaphosphate or ethylenediamine tetra-acetic acid, to prevent the activation of silica by iron ions in this stage.

It will be understood that the amine employed in the second flotation stage may be employed as an acetate because the amine acetate is water soluble and its use is more convenient.

The use of an amine in the acetate form in the first stage is not recommended because of the activating effect of acetate ion on calcite.

ln the rst flotation step, the particular amine employed may result in excessive frothing. Such excessive frothing may be controlled by using a relatively minor quantity of a second amine.

A flow sheet illustrating by way of example one manner of carrying out the present invention is shown in the accompanying drawing.

The following are examples of the process of the invention:

Example l Sovite is ground and conditioned with commercial reagents in the following proportions:

Amine 220 is sold by Carbon and Chemicals Corporation and is believed to consist predominantly of aliphatic monoamines containing 18 carbon atoms. The minor amount of Duomeen T is used to prevent excessive frothing. It is sold by Armour & Co. and consists of aliphatic diamines containing 16 and 18 carbon atoms. These amines are believed to contain substantial proportions of the corresponding fatty acids from which they are made'. Ultrawet 40A is believed to consist of alkyl aryl sulphonates.

The conditioned pulp is subjected to froth flotation to float the pyrochlore and other minerals away from the bulk of the calcite and apatite. The tailing from this operation is substantially free from pyrochlore and is discarded. The float product is cleaned by floating without further reagent addition and the tailing .from this cleaning operation can be tabled to recover any coarse pyrochlore which fails to float.

The concentrate is then treated with 20 lbs/ton of concentrate (9 kg./metric ton) of 10% lsodium silicate solution and 0.25 lb./ ton of concentrate gin/metric ton) of methyl isobutyl carbinol, and subjected to froth flotation to iioat sulphides and fine mica. The tailings, containing the pyrochlore, pass to a wet magnetic separator for the removal of magnetite and some ilmenite.

The pyrochlore-containing material is then conditioned with laurylamine acetate 1.2 lbs/ton of material (600.

to froth flotation to iioa-t the pyrochlore away from silica, coarse mica and silicates. The pyrochlore concentrate thus produced may contain some 45-50% Nb2O5 with a recovery of about 70%, compared to 0.46% Nb205 in the originalore.V 5,0% Nb205` is equivalent to approximately 810% pyrochlore. The concentrate contains minor proportions of pyrrhotite, ilmenite, apatite, quartz and actinolite. l

Examplev Il Dnorneen'1fernulsified with Calsolene Oil HS, was addedfto; theA ground sovite in the following proportions:

Lbs/ton Duomeen T -.5 Calsolene :Oil HS 0.4

The resultant pulp was subjected' to a first froth flotati0nusing.methylisobutyl carbinolas a frothing agent.

Subsequent steps were conducted as in Example I, with the` following results:

Concentrate- 4.4% Nb2O5 Tailing 0.04%'Nb205 Example III DuomeenT, emulsified with Lissapol- N, was addedy to the groundv sovite in the following proportions:

Lbs/ton Duomeen T 0.5 IiissanoLN. 0.1

Thepulp was subjected to froth flotation, after which thel procedure of Example I, following the first Iiiotation step, was carried out, -with the followingresults:

Concentrate 6% Nb205 Tailing 0.04% Nb205 Recovery 93.4%

' Example IV Amine 220 was added to the ground sovite in the proportionV of 0.5. lb./ton. The pulp was subjected to a first froth flotation step,- and the procedure continued as. in Example I.v The results. were:

The pulp was subjected to a first flotation step, and the procedure continued as in Example I. The results were:

Concentrate 13% Nb2O5 'Failing 0.13% Nb205 Recovery 81.9%

Example Vl Rosin Amine -D Acetate was added in varying amounts to the ground sovite and the procedure of the previous examples followed. The results were as follows:

(Ioncentratlon of Rosin Amine D Acetate (in 1bs./

short t0n) 0.60 0.30 0.15 Wt. ofiConcentrate (in grams) 251 259 112 Wtoftailing (in grams) 24.5 238 385 Percent N biO in Concentrate 0.8 0. 6 1. 2 Percent -Nbi in Tailing..- 0. 04 0. 04 0. 32l Calculated Head Assay 0. 48 0.53 PereenbN-bzOs Recovered in the-Concen at 94. 3 50. 7

Iclaim: 1. A. process Ifor the` separation ofpyrochlore from mineral ore containing calcite, apatite and silica which comprises subjecting the ore to froth flotation in the presence of at least one reagent selected from the group consisting of monoamines and diamines containing 14 to 22 carbon atoms in thev molecule to float the pyrochlore and silica away from the calcite and apatite, treating -the float product with a depressant in a quantity sufficient to neutralize the activating effect of said reagent, and thereafter subjecting the product to a selective froth flotation step to oat the pyrochlore away lfrom the silica.

2. A process for the separation of pyrochlore as defined in claim 1, wherein thepH of said product to be subjeoted to said selective froth flotation step is adjusted to 5.5 to 6, and said selective froth flotation step is carried out in the presence of dodecylamine.

3. A process for the separation of pyrochlore from mineral ore containing calcite, 'apatite and silica which comprises subjecting the ore to froth flotation in themineral ore containing calcite, apatite and silica which comprises subjecting the ore to froth otation in the presence of a reagent selected from the group consisting of monoamines and diarnines containing from 14 to 22 carbon atoms in the molecule, land in the presence of an anionic wetting agent to float the pyrochlore and silica -away from thecalcite and apatite, treating the oat product witha depressant in a quantity sufficient to neutralize the activating effect of said reagent,` and thereafter subjectingl the product to froth flotation in the presence of an aliphatic monoamine containing from 10 to 12 carbon,

atoms inthe molecule to float fthe pyrochlorev away from' the silica.

5. A process for the separation of pyrochlore from mineral ore containing calcite, apatite and silica whichl comprises subjecting the ore to froth flotation in the presence of areagent selected from the group consisting of. rnonoarnines` and diamines containing from 14 to 22 carbon atoms in the molecule, and in fthe presenceV of an,

anionic wetting agent which is an alkyl aryl sulphonate.

to float the pyroclilore 4and silica away from the calcite and apatite, treating the float product with a depressant in a quantity sufficient 'to neutralize the activating effect of said reagent, andthereafter subjecting the product to froth flotation in the presence of an aliphatic monoamine containing fromV 10 to 12 carbon atoms in the molecule to float the pyrochlore away from the silica.

6. A process for the separation of pyrochlore from. a mineral ore containing calcite, apatite, silica and iron which comprises subjecting the ore to froth flotation in the presence of a reagent selected from the group consisting of monoamlines and diamines containing from 14 to 22 carbon-atoms in the molecule, to float the pyrochlore and silica away from the calcite and apatite, treating the float product with a depressant in a quantity suicient4 torv neutralizethe activating effect of said reagent andy there-V after subjecting the product to froth flotation inthe presence of an aliphatic monoamine containing from l0 to 12' carbon atoms in the molecule and in the presence of anl agent which forms'a complex io-n with iron to oat the pyrochlore away from the silica.

7'. A process for the separation of pyrochlore from sovite which comprisessubjecting the sovite to frothflotation inthe presence of Ya reagent selected from the group, consisting of monoamines and diamines containing from,

References Cited in the le of this patent UNITED STATES PATENTS Lawver Oct. 21, 1952 Last et al. Mar. 3, 1959 OTHER REFERENCES Taggart: Handbook of Mineral Dressing, John Wiley and Sons, Inc., New York (1.945), pages 12-16. 

1. A PROCESS FOR THE SEPARATION OF PYROCHLORE FROM MINERAL ORE CONTAINING CALCITE, APATITE AND SILICA WHICH COMPRISES SUBJECTING THE ORE TO FROTH FLOTATION IN THE PRESENCE OF AT LEAST ONE REAGENT SELECTED FROM THE GROUP CONSISTING OF MONOAMINES AND DIAMINES CONTAINING 14 TO 22 CARBON ATOMS IN THE MOLECULE TO FLOAT THE PYROCHLORE AND SILICA AWAY FROM THE CALCITE AND APATITE, TREATING THE FLOAT PRODUCT WITH A DEPRESSANT IN A QUANTITY SUFFICIENT TO NEUTRALIZE THE ACTIVATING EFFECT OF SAID REAGENT, AND 